A 72-second radio burst from deep space has never been explained
On August 15, 1977, astronomer Jerry Ehman was reviewing printouts from Ohio State University's Big Ear radio telescope when he spotted an unusually strong, narrowband signal, far louder than background noise, lasting the full 72-second window the telescope could observe any point in the sky. He circled the data and wrote 'Wow!' in the margin. Despite extensive searches, nothing like it has been detected again from that patch of sky, and no confirmed explanation has ever been established.